Intra-Esophageal Balloon System

ABSTRACT

A balloon is provided for selectively moving an esophagus away from an ablation site. The balloon is received through an oral cavity and into the esophagus of a patient. A deflecting member is provided in the tube, the balloon, or both, to selectively distort to bend the balloon and/or the tube to move the esophagus away from the ablation site. The deflecting member may comprise at least one of a strip made of a shape memory material that is responsive to the receipt of a stimulus to deflect to a predetermined shape, a strip that is made of or contains a ferrous material and that deflects in response to the presence of a magnetic field, and a selectively tensionable cable, wire, or string. The deflecting member may be supplemented by a stiffening strip that is located in the balloon and that causes the balloon to expand circumferentially and asymmetrically when inflated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Pat. App. Ser, No. 16,007,461,filed Jun. 13, 2018 and entitled INTRA-ESOPHAGEAL BALLOON SYSTEM, whichis continuation-in-part of U.S. Pat. App. Serial No. 15/786,707, filedOct. 18, 2017, and entitled METHOD OF USING AN INTRA-ESOPHAGEAL BALLOONSYSTEM; which is a divisional of U.S. Pat. App. Serial No. 12/847,018,filed Jul. 30, 2010, and entitled INTRA-ESOPHAGEAL BALLOON SYSTEM; whichclaims priority from U.S. Provisional Pat. App. Serial No. 61/272,564,filed on Oct. 6, 2009, the entire contents of each of each of which ishereby expressly incorporated by reference into the present applicationin its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention generally relates to atrial ablation procedures. Moreparticularly, the invention relates to an apparatus for moving apatient’s esophagus away from an ablation site to prevent accidentaldamage to the esophagus during the performance of an ablation.

2. Discussion of the Related Art

One method of treating atrial fibrillation has been to perform ablationof selected areas of the left atrium. Typically, ablations of this typeare carried out via an intravascular catheter using radiofrequency ormicrowave energy to cause thermal damage to the selected parts of theleft atrial tissue. The posterior wall of the left atrium isparticularly targeted for ablation because the pulmonary veins enter theatrium at this area of the left atrium. Thus, encircling the pulmonaryveins with continuous rings of lesions is common in this procedure. Theesophagus may, however, be positioned so as to overlie one or more ofthese veins, thereby making the desired encirclement difficult orimpossible. Further, the esophagus is a mobile structure. Thus,peristaltic movements thereof may cause the esophagus to move and changeits position relative to the left atrium.

In addition to the foregoing disadvantages, left atrial ablation of thiskind also experiences a great deal of unwanted heat dissipation from theablation catheter tip. Upon application of the catheter tip to theablation site, the tissue immediately contiguous to the tip is heated,thereby disrupting cellular function thereof. A sufficient amount ofheat must be generated to coagulate and denature the proteins in themyocardial cells. If a heat sink is present in close approximation ofthe ablation site, generating sufficient heat becomes difficult if notimpossible using presently available RF generators. For instance,arteries in close approximation to the ablation site experience rapidblood flow sufficient to conduct heat away from the area rapidly.

Left atrial ablation may also be accomplished by introducing a ballooninto the left atrium that can be filled with vaporized nitric oxide,thereby causing ablation by freezing the target tissue. This balloon isgenerally positioned at the mouth of the pulmonary veins and createsring cryo-lesions around the vein orifices, thus isolating them from therest of the left atrium. It may also be positioned to create additionallesions on the roof, the posterior wall, or encircling lesions aroundthe left atrial appendage. It has been shown that cryoablation carriesequivalent risk of injury to the esophagus as radiofrequency energy, anda greater risk of phrenic nerve damage.

The inventor of the present application previously developed anintra-esophageal balloon system for selectively moving the esophagusaway from an ablation site. That system is disclosed in U.S. Pub. App.No. 2011/0082488 (the ‘488 publication), which is incorporated herein byreference herein. The system disclosed in the ‘488 publication ischaracterized by a balloon that is constructed primarily of a flexiblematerial and that is adapted for insertion into a patient’s body throughthe oral cavity of the patient and into the esophagus. The balloon isprovided at the distal end of a tube through which pressurized fluid canflow from an external pressure source to inflate the balloon. Theballoon has a stiffening strip that extends axially or longitudinally ofthe balloon and that is attached to or formed on or in the wall of theballoon. Due to the provision of this stiffening strip, the balloonexpands asymmetrically upon inflation to force the esophagus whichcontains the balloon to also bend and move away from the posterior wallof the atrium. Bending of the esophagus may be directed to also push thephrenic nerve away from the pulmonary veins. The balloon may be inflatedby a fluid such as air or another inert gas or, more preferably, by acooled liquid that permits the balloon to also serve as a heat sink.Protection against damage to the esophagus thus can be accomplished bydeflecting the esophagus away from the lesion site, and by creating aheat sink (in this case warmed liquid) infused into the balloon

The system disclosed in the ‘488 publication works very well. However,it has been discovered that more controlled and, in some instances, morepronounced esophageal movement may be desired.

SUMMARY OF THE INVENTION

In accordance with an aspect the present invention, an intra-esophagealdevice of the general type disclosed in the ‘488 publication can beimproved by providing a deflecting member instead of or in addition tothe stiffening strip. The deflecting member may be provided in the tube,the balloon, or both, so as to selectively distort to bend the balloonand/or the tube to move the esophagus away from the ablation site. Thedeflecting member may comprise at least one of 1) a strip that is madeof a shape memory material that is responsive to the receipt of astimulus to deflect to a predetermined shape, 2) a strip that is made ofor that contains a ferrous material and that deflects in response to thepresence of a magnetic field, and 3) a selectively tensionable elementsuch as a cable, wire, or string. The deflecting member may besupplemented by a stiffening strip located in the balloon.

In one possible configuration, the deflecting member may be formed froma strip of a shape memory material such as nitinol. Upon application ofthe appropriate stimulus such as heat, the memory material of thedeflecting member assumes its preformed shape, bending the tube and/orthe balloon. The shape memory material strip may be confined in the tubeor may also extend into the balloon.

Upon application of the appropriate stimulus such as heat, the memorymaterial of the deflecting member assumes its preformed shape, bendingthe tube and carrying the balloon and esophagus with it. One possibledeflected shape of the tube may be in a curve, such as the letter C,when the balloon is viewed from the side or in transverse cross section.The deflecting member may be continuous with a stiffening strip in theballoon, which may or may not also have shape memory. If the stiffeningstrip in the balloon is continuous with the deflecting member in thetube, and both are made of shape memory material, maximal deflection ofthe esophagus is possible.

Alternatively, a deflecting member could extend into the balloon, and astiffening strip can be provided diametrically opposite the deflectingmember.

The deflecting member may include a tube having a channel with atensionable element such as a fine string, cable, or wire attached tothe distal end of the tube or even the distal end of the balloon. Inthis case, deflection of the tube carries the balloon and esophagus withit. The tensionable element may alternatively be attached to the distalend portion of the balloon.

Another deflection method comprises a central compartment in the balloonwhich contains ferromagnetic material in the form of spheres, powder, orfragments. Application of a magnetic impulse from an electromagnet,possibly positioned posterior to the heart, i.e., under the patient,will pull the balloon and esophagus away from the left atrium. Theferrous object could alternatively comprise a ferrous strip provided onor in the wall of the balloon. This method may be used alone, or inconjunction with one of the other deflection methods described herein.Application of a magnetic field from one side may allow deflection ofthe balloon and esophagus to that side as well.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention are illustrated in theaccompanying drawings, in which like reference numerals represent likeparts throughout, and in which:

FIGS. 1A-1C are schematic illustrations of a patient having anintra-esophageal balloon system constructed in accordance with apreferred embodiment the invention inserted into the patient’sesophagus;

FIGS. 2A-2C are somewhat schematic side sectional elevation views of anintra-esophageal balloon system constructed in accordance with a firstembodiment of the invention and characterized by a deflecting memberlocated in the balloon and formed from a shape memory material, andshowing the balloon in various operational states;

FIG. 2D is a sectional end view of the balloon in the inflated statedepicted in FIGS. 2B and 2C;

FIGS. 3A-3C are somewhat schematic side sectional elevation views of anintra-esophageal balloon system constructed in accordance with a secondembodiment of the invention and characterized by a ferrous strip locatedin the balloon;

FIGS. 4A, 4B, and 4D are somewhat schematic side sectional elevationviews of an intra-esophageal balloon system constructed in accordancewith a third embodiment of the invention and characterized by a tubecontaining ferrous items located in the balloon;

FIG. 4C is a sectional end view of the balloon in the inflated statedepicted in FIG. 4B;

FIGS. 5A and 5C are somewhat schematic sectional elevation various viewsof an intra-esophageal balloon system constructed in accordance with afourth embodiment of the invention and characterized by a deflectingmember located in the balloon and a stiffening strip located in anopposite side of the balloon;

FIG. 5B is a sectional end view of the balloon in the inflated statedepicted in FIGS. 5A and 5C;

FIGS. 6A and 6C are somewhat schematic side sectional elevation views ofan intra-esophageal balloon system constructed in accordance with afirth embodiment of the invention and characterized by a deflectingmember extending the entire length of the balloon and the distal endportion of the tube and formed from a tensionable element;

FIG. 6B is a sectional end view of the balloon depicted in FIG. 6A;

FIGS. 7A and 7B are somewhat schematic side sectional elevation views ofan intra-esophageal balloon system constructed in accordance with asixth embodiment of the invention and characterized by a stiffeningstrip located in the balloon and a deflecting member confined to thetube and formed from a tensionable element;

FIGS. 8A and 8B are somewhat schematic side sectional elevation views ofan intra-esophageal balloon system constructed in accordance with aseventh embodiment of the invention and characterized by a deflectingmember extending the entire length of the balloon and the distal endportion of the tube and formed from a strip of a shape memory material;and

FIGS. 9A and 9B are somewhat schematic side sectional elevation views ofan intra-esophageal balloon system constructed in accordance with aneighth embodiment of the invention and characterized by a stiffeningstrip located in the balloon and deflecting member confined to the tubeand formed from strip of a shape memory material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and initially to FIG. 1A, a schematicillustration of a portion of the internal organs of a patient 10 isprovided with an intra-esophageal balloon system 20 constructed inaccordance with a preferred embodiment of the invention insertedtherein. Patient 10 has a mouth 12 leading to the esophagus 14, whichthen terminates at an opening of the stomach 16. The esophagus 14 is inclose proximity to patient’s heart 18, placing the esophagus at risk toinjury during left atrial ablation. The intra-esophageal balloon system20 is inserted through the patient’s mouth 12 and oral cavity 13 andinto the esophagus 14. In particular, a balloon 22 of the system 20 ispositioned within the esophagus 14 at a point substantially lateral to aleft atrium 24 of the heart 18. Balloon 22 comprises a proximal or upperend 26 and a distal or lower end 28 opposite proximal end 26. Proximalend 26 is interconnected with a tube 30 that extends upwardly throughthe esophagus 14 and through patient’s mouth 12 to a source ofpressurized liquid. The balloon 22 and/or tube 30 are designed to bend,distort, or otherwise move the esophagus 14 away from the heart 18 andfacilitate left atrial ablation without thermal injury to the esophagus.Balloon 22 may be configured to be inflated to pressures ofapproximately 8-10 atmospheres. When balloon 22 is inflated, balloon 22may be 4-7 cm long and less than or equal to 3.0 cm in diameter,although alternative ranges are envisioned and are within the scope ofthe present invention. A relief valve (not shown) may if desired bedisposed at the distal end 28 of the balloon 22 to prevent itsover-inflation. The balloon 22 preferably is inflated with a liquid suchas saline, admixed with radiopaque contrast material, although air oranother inert gas could be used to inflate balloon 22.

Balloon 22 comprises an elongate, relatively narrow body 50 constructedof silicone, rubber or a similar flexible material that may be safelyintroduced into the esophagus. Body 50 is generally circular incross-section when uninflated so as to be symmetrical about alongitudinal bisector, though it is contemplated that the balloon 22 maybe more ovoid or have other shapes, so long as the balloon can beinserted into the patient’s esophagus 14 in its deflated state andinflated as discussed below.

Balloon 22 is configured to distort, move, and/or to expandasymmetrically when inflated so as to distort the esophagus 14 away fromthe heart 18 using one or more deflecting members and/or one or morestiffening strips as described in more detail below. Asymmetricalexpansion may be made possible by rendering the ballooncircumferentially non-uniformly flexible. Stated another way, theballoon includes a first portion and a second portion that is moreflexible than the first portion. This effect is most easily achieved bymaking at least one side or edge portion of the balloon more or lessflexible than at least one other side or edge portion of the balloon. Inuse, the esophagus 14 ordinarily overlies the left atrium as shown inFIG. 1B. The location of the pulmonary vein orifices is marked. Theesophagus is seen to overlie the orifice of the veins. Cryoablation ofthese veins would result in damage to the esophagus. Deflection of theballoon 22 and possibly the tube 30 in response to operation of astiffening strip and/or the deflecting member, however, moves theesophagus 14 away from the orifice of the pulmonary vein as shown inFIG. 1C, avoiding damage from thermal injury.

Referring to FIGS. 2A-2D, a balloon 22 and double-lumen tube 30 areillustrated with a first embodiment of a deflecting member 52. Thedeflecting member 52 of this embodiment is located inside the body ofthe balloon 22 and extends longitudinally of the balloon at leastsubstantially the entire length of the body 50. It may be about as widean average width of a patient’s esophagus or approximately 1 mm to 3 cm.It may be anchored to the inner surface of the body 50 by anchors 54(shown only in FIG. 5C) that allow the deflecting member 52 to slideaxially relatively to the body 50 while preventing any significantrelative circumferential or radial movement therebetween. Deflectingmember 52 is constructed of a shape memory material that may be a metalalloy, such as nitinol, or a shape memory polymer. These materials canbe pre-formed into a specific shape. In the case of nitinol, a chromiumtitanium alloy, application of heat with the material held in itsspecific shape, followed by quenching, results in the nitinol having apreformed shape. The nitinol strip is shaped in the form of a C duringmanufacture. After quenching, the deflecting member 52 is straightenedout to allow easy introduction into the human esophagus (FIG. 2A). Theballoon and esophagus overlie the area of potential thermal injurycaused by radiofrequency ablation or “RF ablation” at this time. Afterdeployment in the esophagus at the time of the procedure, the balloon 22is oriented so that, when the deflecting member 52 achieves itspreprogrammed shape, the entire balloon 22 bends or bows so as to bedisplaced away from the ablation site as shown by the positioning of theballoon 22 in FIGS. 2B and 2C. The resultant displacement of theesophagus can be to one side, or posteriorly away from the esophagus, orboth. The deflecting member 52 may be by the side of the balloon 22closest to the thermal source as shown in FIG. 2B or on the side of theballoon 22 that faces away from the thermal source as seen in FIG. 2C.In either event, the deflecting member 52 deflects the balloon 22 andesophagus away from the thermal source

Several methods are available to activate the preprogrammed shape of thedeflecting member 52. These methods include the achievement of aspecific temperature by the shape memory material, e.g., warming by bodytemperature or injection of hot water into the balloon; by the passageof an electric current to the strip; by the application of RF or X rayenergy to the strip; by activation by a light source introduced into theesophagus; or by the use of a magnetic field. Variations in alloycomposition and duration of heating allow the tailoring of the“triggering temperature” in the case of nitinol. While heating the shapememory material may be the most convenient method of triggering, theother methods outlined above may also be used.

Various polymers are also available which have shape memory.

Alternatively, the deflecting member 52 may be a flexible structure thatdoes not expand or increase in length, but that can bend sideways.

Examples of deflecting members responsive to magnetic fields areillustrated in FIGS. 3A-4C. Referring first to FIG. 3A, the deflectingmember 62 could be formed from a ferromagnetic strip mounted on or inthe sidewall of the body 50 of the balloon 22. The side of the balloon22 bearing the strip 62 is positioned in the esophagus adjacent the leftatrium in use as seen in FIG. 3B. Strip 62 is responsive to operation ofan electromagnet 66 to so that the balloon 22 distorts as whole to movethe esophagus away from the left atrium as shown in FIG. 4C.Alternatively, the deflecting member 72 could be formed from a tube 74containing small ferrous objects 76 such as iron fillings or small ballbearings as shown in FIGS. 4A-4C. The tube 74 could be a central channelin the balloon 22. The side of the balloon 22 bearing the strip 62 or 72is positioned in the esophagus adjacent the left atrium in use.Deflecting member 62 or 72 may be responsive to operation of anelectromagnet 66 to cause the balloon 22 to distort to move theesophagus away from the left atrium. The magnet 66 may be positionedbeneath a supine patient as shown in FIG. 4C, or it may be positioned tothe posterior to the esophagus as shown in FIG. 4D. In both cases, theballoon 22 may be filled with warm water prior to cryoablation so thatthe balloon 22 acts as a heat sink. The amount of deflecting member andesophagus movement can be controlled by controlling the strength of themagnetic field generated by magnet 66 and/or the distance between themagnet 66 and the deflecting member 62 or 72.

In all cases described above, the deflecting member could be provided inat least the distal end portion of the tube 30 instead of or in additionto being provided in the balloon 22.

It is also possible to provide a stiffening strip on or in the balloon,either alone or in combination with a deflecting member. The stiffeningstrip causes asymmetrical expansion of the balloon by rendering theballoon circumferentially non-uniformly flexible. The stiffening strip,if present, preferably is applied along one relatively peripheral narrowportion of balloon at a location at or near the portion of the esophagus14 that is closest to the patient’s heart 18 and extends lengthwise fromproximal end 26 to distal end 28 without extending distally beyond thedistal end. Stiffening strip preferably has a width similar to that ofan average width of a patient’s esophagus for reasons that will be madeapparent from the ensuing description. In particular, stiffening stripmay have a width of approximately 1 mm to 2 cm. In particular,stiffening strip is configured to inhibit or prevent a portion ofballoon 22 from expanding during inflation of balloon 22.

Referring to FIGS. 5A-5C, a stiffening strip 84 is shown in combinationwith a deflecting member 82, with the elements 82 and 84 being locatedon opposite sides of the balloon 22. More specifically, the deflectingmember 82 is formed from a nitinol strip or a strip of another materialhaving a shape memory. This deflecting member could be provided on or inthe sidewall of the body 50 of the balloon 22 and could extendlongitudinally along at least the entire length of the balloon 22. Alongitudinally extending stiffening strip 84 is provided on or in thesidewall of the body 50 diametrically opposite the deflecting member 82.The stiffening strip 44 could be formed, for example, from a piece ofrelatively rigid plastic or a metal wire. It also could be formed from ashape memory material. In this case, inflation of the balloon 22 causesthe balloon 22 to deflect away from the ablation site as shown in FIG.5C, and activation of the shape memory material of deflecting member 82aides in this deflection.

Referring to FIGS. 6A-6C, the deflecting member 92 may include alongitudinally extending channel 93 in the double-lumen tube 30 and thebody 50 of the balloon 22 for receiving a tensionable element 94, suchas a fine cable, wire. The tensionable element 94 has a proximal endextending beyond proximal end of the tube 30 and a distal end affixed tothe distal end of the balloon 22. The portion of the deflecting member92 that is located within the balloon 22 may be imbedded in a strip 96that is stiffer than the remainder of the balloon 22 but that isflexible enough to bend or distort with the deflecting member 92. Inuse, retraction of the tensionable element 94 pulls the distal end ofthe balloon 22 toward the proximal end to cause deflection of theballoon 22. Retraction may be accomplished by a screw mechanism 98 orsimilar mechanism in a handle 100 located at or beyond the proximal endof the tube 30. In a variant, shown in FIGS. 7A and 7B, the channel 103of the deflecting member 102 extends only the length of the tube 30,with the inner end of the tensionable element 104 being anchored to theproximal end of the balloon 22. A longitudinally extending stiffeningstrip 110 is located in or on the balloon 22 in alignment with thechannel 103. With this arrangement, inflation of the balloon 22 leads toasymmetric expansion as discussed above, and additional balloon and tubemotion movement are achieved by manipulation of a screw mechanism 108 topull the distal end of the tube 30 toward the proximal end as shown inFIG. 7B.

Other combinations also could be used to deflect both the balloon 22 andthe tube 30.

For example, as shown in FIGS. 8A and 8A, a deflecting member 112 formedfrom a strip of nitinol or other material having a memory shape couldextend the entire longitudinal length of the balloon 22 and through atleast the distal end portion of the double-lumen tube 30. The deflectingmember 112 could be mounted on or imbedded in the wall of the balloonbody 50 and/or the tube 30.

Alternatively, referring to FIGS. 9A and 9B, the nitinol or other memorymaterial forming the deflecting member 122 could extend only the lengthof the tube 30 or at least the distal portion thereof, and a stiffeningstrip 124 could be located in or on the balloon 22 in alignment with thedeflecting member 122. With this arrangement, inflation of the balloon22 leads to asymmetric expansion due to the presence of stiffening strip124, and additional balloon and tube motion are achieved by distortionof the shape memory material forming the deflecting member 122 upon thereceipt of an appropriate stimulus such as temperature change, magneticattraction, UV exposure, etc.

The devices described herein, and other devices falling within the scopeof the present invention, can also protect the esophagus against injuryduring cryoablation. In cryoablation, specific portions of the leftatrium are cooled to subzero temperatures, usually by the application ofan occluding balloon to the orifices of the pulmonary veins. Theoccluding balloon is then filled with vaporized nitrous oxide, therebycreating a ring of cryo-damaged atrial tissue surrounding each pulmonaryvein. The damaged tissue does not conduct electrical impulses, and itserves to “isolate” the pulmonary veins from the rest of the atrium.

It has been shown that cryoablation is also associated with the samerisk of esophageal damage seen with RF ablation, when the esophagus iscontiguous to the pulmonary veins.

To prevent cryo-damage to the esophagus, two strategies are availablewith the esophageal balloon:

-   a) Preheating the esophagus with warmed saline for several minutes    prior to application of cryoenergy and retaining warmed fluid during    cryoablation.-   b) Deflection of the esophagus away from the cryo-site using any or    all of the methods used for deflection during RF ablation.

Pre-warming and warming of the esophagus are unlikely to provide thesame degree of protection as cooling the esophagus during RF. Theesophagus may be safely heated to about 110° F., i.e., 12° F. higherthen body temperature. It can be safely cooled to 5° F., a 93° F.differential. It has been shown in animal studies and in vitro thatpre-cooling the esophagus with a balloon using saline at 5° C. preventsthermal damage to the esophagus during RF of the atrial tissue. The samehas not been shown with pre-warming or warming of the esophagus, but itmay be an alternative method of protection.

Deflection of the esophagus becomes more important here, along with someprotection conferred by gentle heating. Heat sensitive shape memorymaterials are likely to be the best option. The introduction of warmwater at, for example, 110° F. to activate the shape memory gives awider range over ambient body temperature, allowing for easier design ofthe shape memory material and avoiding inadvertent activation of thematerial by manual handling or during transportation. (FIGS. 6A and 6B.)

Although the best mode contemplated by the inventors of carrying out thepresent invention is disclosed above, practice of the present inventionis not limited thereto. It will be manifest that various additions,modifications and rearrangements of the aspects and features of thepresent invention may be made in addition to those described abovewithout deviating from the spirit and scope of the underlying inventiveconcept. The scope of some of these changes is discussed above. Thescope of other changes to the described embodiments that fall within thepresent invention but that are not specifically discussed above willbecome apparent from the appended claims and other attachments.

What is claimed is:
 1. An intra-esophageal device comprising: a tubepresenting at least one lumen, the tube having a proximal end and adistal end; a balloon having a proximal end and a distal end, theproximal end having an opening in fluid communication with the lumen inthe tube, wherein the tube and balloon are sized for insertion into ahuman esophagus; and a deflecting member which is located at least inpart in the balloon and which can be selectively activated to cause theballoon to move the esophagus away from an ablation site.
 2. The deviceof claim 1, wherein the deflecting member comprises a strip that is madeof a shape memory material that is responsive to the receipt of astimulus to deflect to a predetermined shape, the deflecting memberextending along at least a majority of a longitudinal extent of theballoon.
 3. The device of claim 2, further comprising a stiffening stripthat is located in the balloon and that extends longitudinally of theballoon, the stiffening strip distorting less than the surroundingportions of the balloon during balloon inflation so that the balloon asa whole expands asymmetrically about a longitudinal centerline thereofto deflect the esophagus away from the ablation site.
 4. The device ofclaim 3, wherein the stiffening strip is positioned on a common side ofthe balloon as the deflecting member and is in alignment with thedeflecting member.
 5. The device of claim 3, wherein the stiffeningstrip is located at least generally diametrically opposite thedeflecting member.
 6. The device of claim 1, wherein the deflectingmember comprises a strip that is made at least in part of a ferrousmaterial and that deflects in response to the presence of a magneticfield.
 7. The device of claim 1, wherein the deflecting member comprisesa tube that contains a ferrous material and that deflects in response tothe presence of a magnetic field.
 8. The device of claim 1, wherein thedeflecting member comprises a tensionable cable that extends along atleast along a distal end portion of the tube and that is tensionablefrom outside of the proximal end of the tube.
 9. The device of claim 8,wherein the tensionable cable also extends along at least a majority ofa longitudinal extent of the balloon.
 10. The device of claim 8, furthercomprising a stiffening strip that is located in the balloon and thatextends longitudinally of the balloon, the stiffening strip distortingless than the surrounding portions of the balloon during ballooninflation so that the balloon as a whole expands asymmetrically about alongitudinal centerline thereof to deflect the esophagus away from theablation site.
 11. The device of claim 8, wherein the tensionableelement comprises one of a cable, a wire, and string.
 12. The device ofclaim 1, wherein, when inflated, the balloon is 4-7 cm long.
 13. Thedevice of claim 1, wherein, when inflated, the balloon has a maximumdiameter of less than 3.0 cm.
 14. An intra-esophageal device comprising:a tube presenting at least one lumen, the tube having a proximal end anda distal end; a balloon having a proximal end and a distal end, theproximal end having an opening in fluid communication with the lumen inthe tube, wherein the tube and balloon are sized for insertion into ahuman esophagus, and wherein, when inflated, the balloon is 4-7 cm longand has a maximum diameter of less than 3.0 cm.; and a deflecting memberwhich is located at least in part in the balloon and which can beselectively activated to cause the balloon to bend or bow to move theesophagus away from an ablation site, wherein the deflecting membercomprises a strip that is made of a shape memory material that isresponsive to the receipt of a stimulus to deflect to a predeterminedshape, the deflecting member extending along at least a majority of alongitudinal extent of the balloon.
 15. The device of claim 14, furthercomprising a stiffening strip that is located in the balloon and thatextends longitudinally of the balloon, the stiffening strip distortingless than the surrounding portions of the balloon during ballooninflation so that the balloon as a whole expands asymmetrically about alongitudinal centerline thereof to deflect the esophagus away from theablation site.
 16. The device of claim 15, wherein the stiffening stripis positioned on a common side of the balloon as the deflecting memberand is in alignment with the deflecting member.
 17. The device of claim15, wherein the stiffening strip is located at least generallydiametrically opposite the deflecting member.